FC 26 crashes with ILLEGAL_INSTRUCTION when connecting online
Description:
The game launches and runs normally in offline mode, but crashes every time it attempts to connect to online services. The crash is 100% reproducible and always occurs at the same address in FC26.exe.
System:
- CPU: AMD Ryzen 4000 series (Family 23, Model 96 — Zen 2 architecture)
- OS: Windows 10 Pro (Build 19045)
- GPU: NVIDIA (discrete) + AMD integrated
Crash details from minidump:
- Exception: STATUS_ILLEGAL_INSTRUCTION (0xC000001D)
- Faulting module: FC26.exe
- Crash address: 0x0000000140E45B80 (RVA: 0x0E45B80) — identical across all crash dumps
- Renderer: DirectX 12
Root cause: The online code path in FC26.exe executes a CPU instruction not supported by Zen 2 processors (likely AVX-512 or similar). Zen 2 supports up to AVX2 but not AVX-512. The offline code path never reaches this instruction, which is why the game works fine without an internet connection.
Steps to reproduce:
- Launch FC 26 on a machine with an AMD Ryzen 4000 series (Zen 2) CPU
- Reach the main menu (game loads fine)
- Connect to online services / attempt any online mode
- Game crashes immediately
What was tried:
- -dx11 launch argument — ignored, game still loads DX12
- Disabling Windows Defender real-time protection — no effect
- Game repair — no change
Crash dumps attached.
